The recent demand for safe and fuel efficient automobiles has created a need for tire rubber materials to achieve a simultaneous improvement in wet-skid properties, fuel economy, and abrasion resistance. However, since these properties have a trade-off relationship, it is usually difficult to achieve a balanced improvement of these properties.
Silica (filler for reducing heat build-up) has been used to solve this problem. However, silica particles tend to aggregate due to the hydrogen bonding of silanol functional groups on the surface, they insufficiently disperse, causing problems such as poor processability.
In this context, techniques using silane coupling agents have been developed to improve dispersion of silica. For example, Patent Literature 1 proposes to use silane coupling agents such as bis(3-triethoxysilylpropyl)tetrasulfide. However, despite the use of such general purpose silane coupling agents, there is a need for further improvement to achieve high degrees of processability and abrasion resistance.